Pen



FIG. 1 is a front elevation view of the pen showing my new design;

FIG. 2 is a rear elevation view of the pen of FIG. 1.

FIG. 3 is a left side elevation view of the pen of FIG. 1.

FIG. 4 is a right side elevation view of the pen of FIG. 1.

FIG. 5 is a bottom plan view of the pen of FIG. 1.

FIG. 6 is a top plan view of the pen of FIG. 1; and,

FIG. 7 is an exploded view of the pen of FIG. 1.

The broken lines in the figures show portions of the pen which form no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 